Do in vitro susceptibility data predict the microbiologic response to amphotericin B? Results of a prospective study of patients with Candida fungemia.
Outcome for 105 patients with candidemia treated with amphotericin B was correlated with amphotericin B in vitro susceptibility results. Thirty-three patients had microbiologic failure, which was defined as persistence of Candida in the bloodstream despite > or = 3 days of amphotericin B. Amphotericin B minimum inhibitory concentrations (MICs) were determined by the National Committee for Clinical Laboratory Standards methodology. After determination of MICs, the minimal lethal concentrations (MLCs) were determined. The isolates tested yielded a narrow range of amphotericin B MICs (0.06-2 microg/mL); only 5% (5/105) exhibited MICs > or = 1 microg/mL. The MLC range, on the other hand, was significantly broader (0.125 to > 16 microg/mL); 24% (25/105) exhibited MLCs > or = 1 microg/mL. The strongest predictor for microbiologic failure was 48-h MLC (P < .001), followed by 24-h MLC (P = .03) and 48-h MIC (P = .11). A resistant break point for amphotericin B of > 1 microg/mL for MLC and > or = 1 microg/mL for MIC could be inferred from this study.
Nguyen
M H
MH
University of Florida College of Medicine, VA Medical Center, Gainesville 32610, USA. nguyen.med@shands.ufl.edu
Clancy
C J
CJ
Yu
V L
VL
Yu
Y C
YC
Morris
A J
AJ
Snydman
D R
DR
Sutton
D A
DA
Rinaldi
M G
MG
D000666:Amphotericin B / Q000494:pharmacology* / Q000627:therapeutic use; D000935:Antifungal Agents / Q000494:pharmacology* / Q000627:therapeutic use; D002175:Candida / Q000187:drug effects*; D002177:Candidiasis / Q000188:drug therapy*; D004352:Drug Resistance, Microbial; D016469:Fungemia / Q000188:drug therapy*; D006801:Humans; D008826:Microbial Sensitivity Tests; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D017211:Treatment Failure; D016896:Treatment Outcome
D000935:Antifungal Agents; D000666:Amphotericin B